The present invention relates in general to extendable truck beds, and more particularly, to a truck bed extension structure and mechanism that will enable the truck bed to extend beyond the frame of a truck and tilt into a slanting position to form a ramp-like structure for convenient loading and unloading.
Many devices and structures for providing a ramp system and extension, which in turn may provide the ramp system, to the truck beds have been known in the art. The basic method to provide a ramp includes tilting of an extended structure such that its rear end touches the ground forming a sloping surface. Detachable ramps are also used to provide the sloping surface. The basic method for providing an extension mainly involves extending the truck bed with appropriate means, manual or automatic, or attaching a separate structure at the rear end of the truck bed.
Numerous structures and mechanisms can be adopted to modify the hauling area of a truck. For example, U.S. Pat. No. 6,461,096 to Mentele discloses a tilt bed for a truck or a trailer that provides a ramp. The tilt bed comprises a frame, and a deck mounted on and supported by the frame, rollers connected to the front portion of the deck, tracks for guiding the rollers, and a hydraulic cylinder with a piston that has a first end connected to the frame and a second end connected to the bed. As the piston moves from an extended state into a retracted state, it causes the trailer bed to move in a rearward position. At the same time, the tracks force the rollers in an upward motion and cause the trailer bed to tilt.
U.S. Pat. No. 6,378,926 to Renze discloses a truck bed extender apparatus for increasing the load capacity of a pickup truck. The apparatus comprises four hinged basic elements including a pair of side panels, a tailgate, and a platform that is secured to the tailgate of the truck. The panels are held in their upright positions by pin locks and removably attached to the sides of the truck bed by adjustable latch brackets. Folding the side panels inward and rotating the assembly by 270 degrees down for loading or unloading can fold the assembly.
U.S. Pat. No. 6,158,797 to Bauer discloses a truck bed extension that is convertible into a ramp. The truck bed extension comprises three panels, including a back wall and two sidewalls, which are hinged together to allow the truck bed extension to be straightened when detached from the truck bed and used as a ramp or ladder. The truck bed extension includes rotational stops or rotational locks which maintain the extension in a straight condition when unfolded for use as a ramp. The rotational stops may take the form of U-channel rails protruding from the outside/bottom of the extension.
In U.S. Pat. No. 6,354,788 to Adams a dump truck with a ramp assembly is disclosed. The truck mainly comprises a conventional frame, a truck bed mounted to the frame, a ramp assembly movably attachable to the rear end of the bed, and hydraulic cylinders. The ramp assembly is selectively moveable between a lowered position and a raised position by actuating the hydraulic cylinders. In the lowered position, the ramp extends from the truck bed downwardly to the ground to allow equipment to be driven onto the back of the truck. In the raised position, the ramp assembly is raised to a position above the bed of the truck to allow the truck bed to be raised to its dumping position.
Although numerous designs and mechanisms of the truck bed assemblies, such as the above devices, are known in the art, there is a need for an efficient and convenient automatic mechanism, which can be achieved by an improved truck bed extension and ramp assembly of the present invention. Other objects of the present invention will become better understood with reference to the appended Summary, Description, and Claims.